1. Field of the Invention
The present invention relates to a portable information terminal that communicates with a network by connecting to a NIC, an IP address setting program, and an IP address setting method.
2. Description of the Related Art
In recent years, information of a large number of portable information terminals are often collectively managed. In such a case, a system in which a NIC (Network Interface Card) having an interface such as USB (Universal Serial Bus) is connected to the portable information terminal and thereby the portable information terminal is connected to a LAN (Local Area Network) through the NIC is used. Further, in such a system, if, under the circumstances in which an unspecified number of potable information terminals are allowed to be connected to a NIC, the NIC is used only when the portable information terminal needs to be connected to the LAN, the number of NICs can be reduced to less than the number of portable information terminals.
As a method of setting an IP (Internet Protocol) address to a NIC adapter to be connected to the potable information terminal, a method in which a static IP address of the portable information terminal is set to the NIC on the OS (Operating System) of the portable information terminal, or a method in which a DHCP (Dynamic Host Configuration Protocol) server installed in the LAN automatically sets the IP address of the portable information terminal to the NIC is available.
As a prior art related to the present invention, Jpn. Pat. Appln. Laid-Open Publication No. 2003-348093 is known. A communication processing apparatus and a network interface switching method in the publication assigns an IP address to a NIC and, when detecting a failure of the NIC, assigns the IP address of the failed NIC to another NIC.
However, in the case of adopting the method in which a user manually sets an IP address on the OS of the portable information terminal, a setting error, such as duplication of IP address, is easier to occur. Further, in the case of using a large number of portable information terminals, thousands of man-hours are involved and an increasing number of static IP address become necessary.
Further, in the case of adopting the method in which a DHCP server within the LAN automatically sets the IP address to the NIC, an IP address is assigned to the portable information terminal every time the terminal is connected to the LAN. Therefore, an unspecified number of portable information terminals are likely to access the LAN. Thus, problem relating to security is caused.
To solve the above problems, a countermeasure in which a DHCP server function is provided for each NIC. However, this increases cost.